Numerous laminated building panels are known in the prior art. The panels are frequently called appearance panels because they are typically embossed with attractive, simulated wood grain patterns and grooves to simulate wood paneling. There is a need to provide inexpensive laminated panels, for exterior surfaces, having improved resistance to delamination of the facing sheets and improved manufacturability. The latter improvement is desirable in order to avoid or at least minimize the formation of bubbles or blisters between the facing sheets and foam core during manufacturing of the panels or during weathering of the panels.
Glass fibers are known in the prior art as high strength and relatively inexpensive reinforcing materials. Consequently, some workers have suggested the desirability of incorporating glass fibers into vinyl panels. For example, Rajewski U.S. Pat. No. 4,308,702 states that glass fibers may be used along with other conventional filler material such as additives, pigments, etc., in rigid plastic building panels produced by profile extrusion of polyvinyl chloride (PVC) and other thermoplastic polymers. Wallen U.S. Pat. No. 5,030,676 suggests a process in which an unplasticized polyvinyl chloride composition can be extrusion coated on a variety of preformed stock materials such as wood, aluminum, glass fibers and the like.
It is also known to form a reinforced plastic laminate structure comprising an elongated reinforcing material such as fiberglass that is encapsulated in extruded plastic material as disclosed by Kohl U.S. Pat. No. 4,788,088.
Hanusa U.S. Pat. No. 4,753,837 discloses a laminated building panel having facing material adhered to one or both faces of a rigid foam core. That patent discloses a three dimensional open mesh structure such as fibers, strands, filaments, or strips of metal, glass, plastic or natural fibers which are either attached to or an integral part of the inside surface of the facing material.
Rothman U.S. Pat. No. 4,078,348 discloses construction panels for structural support systems which include an insulating core with face members made of thermoplastic or thermoset resin reinforced with glass fibers. The glass fibers are incorporated in multidirectional orientation in the resin by applying the fibers onto a layer which has previously been applied to a mold.
It is a principal objective of the present invention to provide a laminated building panel having an outer facing sheet and a foam core and having improved resistance to delamination of the facing sheet and reduced formation of bubbles during manufacture of the panel and reduced blistering of the facing sheet as a result of weathering.
Another objective of the invention is to provide an economical, environmentally acceptable method for producing a laminated building panel.
Additional objectives and advantages of our invention will become apparent to persons skilled in the art from the following detailed description and drawings.